CVE-2026-63994 (GCVE-0-2026-63994)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:56 – Updated: 2026-10-19 20:18
VLAI
Title
tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
Summary
In the Linux kernel, the following vulnerability has been resolved: tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]() Sashiko found that iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr() before an skb_cow() call which can reallocate skb->head. Fix this possible UAF by initializing the local variables after the skb_cow() call. Remove skb_reset_network_header() calls which were not needed.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 15:34 UTC
CWE
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6641 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < 95b6d772bfe788331d9742d73eaa12e113b2adc4 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < 7254aef4d1a7e18e887af9010e2f2dc34806789b (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < bf8b3f34c37c162357138e7c0942723b8b94fed1 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < 76cd9398a0470257ab765bdf5f358a2af2e17934 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < 50750d86a2e5266aba0c295483b3397843198b11 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < 6dff77899b9e9fe5d854abda3a98ad04e7229ef7 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < f3f204541f280a6ecb04503a0d6794d93990ca43 (git)
Affected: 4cb47a8644cc9eb8ec81190a50e79e6530d0297f , < b4bc94353050b1fa7b702bd4c6600710dd926cff (git)
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Linux Linux Affected: 5.9
Unaffected: 0 , < 5.9 (semver)
Unaffected: 5.10.259 , ≤ 5.10.* (semver)
Unaffected: 5.15.210 , ≤ 5.15.* (semver)
Unaffected: 6.1.176 , ≤ 6.1.* (semver)
Unaffected: 6.6.143 , ≤ 6.6.* (semver)
Unaffected: 6.12.93 , ≤ 6.12.* (semver)
Unaffected: 6.18.35 , ≤ 6.18.* (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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}



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Sightings

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Nomenclature

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  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
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Vulnerability timeline

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